Wednesday, September 14, 2011

There are many theories about why individuals engage in heavy alcohol consumption. One general theory psychologists refer to is called the Dual Process Model. It holds that people have two different systems for processing information. The impulsive system automatically (quickly) evaluates stimuli in the environment in terms of emotion, and motivation, and (again quickly) pushes the individual to move toward or away from the stimuli. Alternatively, the reflective system focuses on long-term goals and personal standards but it is slower acting and requires more effort or energy. These two systems constantly battle for supremacy. In the case of drinking, if the impulsive system wins out an individual will likely consume cocktail after cocktail because the drink tastes good, or makes the person feel good. If the reflective system wins out, the individual will likely consume less, or not at all, knowing that in the long-run they will be healthier and happier if they avoid such excess.

The ability of the reflective system to win out, or override automatic impulses and maintain goal-directed action, is accomplished by, what psychologists call, executive functioning. Executive functioning includes a host of different cognitive functions such as planning, attention control, working memory (the ability to maintain and manipulate information), and response inhibition (the ability to override impulsive responses). Unfortunately, research has shown that these executive functions are often impaired in chronic drinkers. First, individuals who start out with poorer executive functioning are more prone to become chronic drinkers if they associate alcohol with feeling good. Even more, excessive drinking has been shown to further impair executive functions. This means that the more one drinks the harder it will be for them to stop drinking.

Though this sounds pretty dire, there have been a host of recent studies showing that executive functions like working memory and response inhibition can be trained. That means with practice people can become better at tipping the scale in favor of their long-term goals (the reflective system), rather than their automatic temptations (the impulsive system). Researcher Katrijn Houben and colleagues at Maastricht University and the University of Amsterdam, tested whether training executive functions, specifically working memory, could boost the supremacy of the reflective system, and thus help heavy drinkers to consume less alcohol.

Method: 48 heavy drinkers were randomly assigned to the executive function training condition or the control condition. In both conditions participants completed three working memory tasks each day for a total of 25 days. For example, during the backward digit span task several numbers appeared on a screen one at a time, and then the participant had to say what the sequence of numbers was, but they had to relay them backwards, in the order opposite to what they originally saw (e.g. if the sequence was 10, 35, 21, 4 the participant would have to say 4, 21, 35, 10).

In the training condition, the working memory games were adaptive. Each of the tasks started with a sequence of 3 items to be recalled. As the participants got better at the task however, the sequence would increase to 4, then 5, and so on. This adaptive increase in difficulty helps individuals to perform better and better. In the control condition, the tasks remained on the easy 3 level throughout the study – which should lead to no improvement in working memory.

To mark participants’ progress their working memory ability and their daily alcohol consumption were tested prior to the training (pre-test), right after the training finished (post-test), and again one month later (follow-up).

Results: As the researchers predicted, and consistent with prior studies, participants in the training condition (those that completed the adaptive working memory games) showed an improvement in working memory from the pre-test to the post-test. This improvement in the training condition was maintained at the one-month follow-up. Participants in the control condition (those who completed the non-adaptive working memory games) showed no such improvements.

In addition participants in the training condition showed a reduction in alcohol consumption from pre-test to post-test, by almost 10 drinks per week on average. Not an insubstantial number! Again, this reduction persisted at the follow-up assessment one month later. Participants in the control condition did not show a reduction in alcohol consumption.

The researchers also found that participants who showed the greatest reduction in alcohol consumption were those who had the strongest automatic tendency to view alcohol positively – a quality they measured with an implicit test of positive attitudes toward alcohol. This evidence suggests that training working memory - strengthening participants’ executive functioning - aided the reflective system to win out over the impulsive system. That is, it helped participants to overcome some of the temptation to drink.

This research is pretty exciting - I mean, who would have thought that building working memory capacity would lead to a reduction in alcohol intake! It provides a very promising avenue for future interventions aimed at curbing alcohol intake in problem drinkers, or alcoholism more generally.

Do you think this is an approach that should be implemented at a broader level? Do you see limitations with the research?

3 comments:

I wonder about other differences that are a part of the memory training. Having a task to do every day that gets progressively more difficult offers the participants in that condition a goal and a chance for success on a daily basis - rather than a boring, repetitive chore that does not challenge them as in the other condition. I would expect there to be some co-morbidity of depression or at least depressive symptoms in these heavy drinkers and I think this could interact with the tasks. Giving depressed-type, heavy drinking people a goal, a challenge, a chance for success on a task, etc. on a daily basis could be motivating them to stay focused on longer-term goals and success, which is not something that the other group receives. A lack of goals and motivation are the typical symptoms of depression, and a perfect reason to drink!

Hi Dan-Interesting comment. The non-adaptive working memory control seems to be common in training studies of this nature. Others have matched their experimental group to a control that only did the pre-test and post-test. Agreed, it could be possible that for these heavy drinkers the training increased self-efficacy beliefs in addition to working memory capacity - thus explaining the decrease in drinks/week. An important question future research should address. Thanks for reading!Anna